1. Field of the Invention
The invention relates to a method and apparatus for the early diagnosis and localization of dental caries.
2. Description of Relevant Materials and Background
Until recently, there was little reason to be concerned with attempting to localize the development of dental caries, other than from a theoretical viewpoint. Practically speaking, no techniques were available to arrest the development of dental caries and early information as to their existance was of little practical use.
Recently however, developments in dental science such as the use of polymeric sealants have made it possible to arrest the growth and development of dental caries such that it is now of considerable practical interest to be able to determine and localize the early presence of dental caries so that their further development may be arrested.
Traditional examination techniques such as x-rays and examination with a dental explorer are capable of detecting the presence of dental caries only at relatively late stages of development when the development can no longer be arrested by newly developed techniques. Furthermore, the use of such techniques on a regular basis is limited because of the health dangers associated with radiation, as well as the discomfort, and possible damage to the patient since it has been shown that probing with an explorer damages the dentine in incipient caries. Furthermore, performance of such techniques requires trained personnel and does not allow for detection by the patient himself, for example.
It would, therefore, be very desirable to provide a technique which allows for the early detection and localization of dental caries by a procedure which is simple to perform, even by untrained personnel, and which is not disturbing to the patient, as has traditionally been the case.
Although techniques have now been developed which yield a general measure of cariogenic microorganism activity in the mouth, none of the available techniques actually localizes the site of the cariogenic activity.
STARK, U.S. Pat. No. 3,279,068, discloses a method of detecting carious tissue and dental calculus. The patent discloses that 9-aminoacridine and its hydrochloride are unique agents for disclosing the presence of dental caries and calculus. The patent does not discuss the detection of Streptococcus mutans (S. mutans) or other cariogenic microorganisms.
GREEN, U.S. Pat. No. 3,332,743, discloses a diagnostic test for dental caries activity. The test gives a color response at room temperature, based on the sum total of metabolic activity of the saliva (column 1, line 60). In accordance with that test, a buffered substrate solution containing a suitable indicator dye measures the oxidation rate of a saliva specimen by measuring the time period in which the indicator dye undergoes a distinct color change, which is taken as a measure of dental caries activity (column 1, line 70). The test does not provide spatial localization of microorganisms associated with the cariogenic activity.
HOERMAN et al., U.S. Pat. No. 3,746,625, discuss a 48-hour test for S. mutans in plaque. The method involves removing a series of specimens from the patient's mouth, generally by insertion of dental floss between the teeth to remove material in the mouth adjacent to the tooth (column 1, line 60).
The floss with the specimen on it is dropped into a test solution. After a 48-hour period, a yellow color indicates the presence of S. mutans (column 1, line 65 and column 2, line 15).
There is no disclosure of localizing cariogenic activity to a specific area of a tooth. Moreover, dental floss, when inserted between two teeth will naturally sample one surface of each tooth at the same time. Additionally, since cariogenic activity is not limited to S. mutans, a test limited to this analyte may not be completely accurate.
STEARNS et al., U.S. Pat. No. 3,903,252, describes a dental disclosing composition to be used in the mouth. A staining agent associated with the composition adheres to plaque on the teeth. However, the presence of plaque on the teeth does not necessarily indicate the presence of microorganisms which cause cariogenic activity. Thus, dental disclosing compositions, as exemplified by this patent, do not localize cariogenic activity.
NAKAMURA et al., U.S. Pat. No. 4,359,455, disclose a diagnostic test composition for dental caries activity. The composition contains a saccharide as a carbon source for promoting the acid-producing capacity of bacteria in the mouth as well as a pH indicator which has a color change point at a pH range of 5 to 7. According to the method, a sample of dental plaque is collected and introduced into the composition, and then the change of color of the pH indicator contained in the composition is observed with the naked eye (column 1, line 52). Thus, the composition constitutes an overall measure of bacterial activity in the mouth, and is not intended to localize the activity.
DEYLOFF, U.S. Pat. No. 4,468,456, discloses a medium for differentiating S. mutans. The patent contemplates the innoculation of a culture medium with samples taken from the mouth (column 6, line 30). There is no disclosure showing the localization of cariogenic activity to specific areas of the teeth.